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PubMedDate not supplied

Experimental Chagas' disease in rhesus monkeys. I. Clinical, parasitological, hematological and anatomo-pathological studies in the acute and indeterminate phase of the disease.

Rhesus monkeys (Macaca mulatta) were infected subcutaneously with 1.0 x 10(4) to 1.5 x 10(4) metacyclic trypomastigotes of Trypanosoma cruzi (Colombian strain). Parasitological and immunological parameters were evaluated in these animals for periods of 1 month to over 3 years. A chagoma was observed between the 3rd and the 13th day after infection (a.i.) and patent parasitaemia between the 13th and 59th day a.i.. Thereafter, parasites were demonstrated only by haemoculture and/or xenodiagnosis. Circulating specific IgM and IgG antibodies were observed as early as in the 2nd week a.i. IgG levels persisted until the end of the experiment, but IgM antibodies were detectable nine months a.i. Haematological alterations comprised leucocytosis and lymphocytosis. Electrocardiographic alterations were minor and transient, similar to those observed in non-lethal human acute Chagas' myocarditis. Myocarditis and myositis, characterized by multiple foci of lympho-histiocyte inflammatory infiltrate, were present in monkeys sacrificed on the 41st, 70th and 76th day but not in the animal sacrificed 3 years and 3 months a. i.. The results suggest that Chagas' disease in rhesus monkeys reproduces the acute and indeterminate phases of human Chagas' disease.

Animals↗
PubMedDate not supplied

Clinical, parasitological and immunological aspects of experimental infection with Trypanosoma evansi in dogs.

This research investigated the pattern of antibody response by means of enzyme linked immunosorbent assay (Elisa) and indirect fluorescent antibody test (IFAT) through the course of experimental Trypanosoma evansi infection in dogs. Clinical and parasitological features were also studied. The average prepatent period was 11.2 days and parasitaemia showed an undulating course. Biometrical study of parasites revealed a mean total length of 21.68mm. The disease was characterized by intermittent fever closely related to the degree of parasitaemia and main clinical signs consisted of pallor of mucous membrane, edema, progressive emaciation and enlargement of palpable lymph nodes. Diagnostic antibody was detected within 12 to 15 days and 15 to 19 days of infection by IFAT and Elisa, respectively. High and persistent antibody levels were detected by both tests and appeared not to correlate with control of parasitaemia

Animals↗
PubMed2002

Parasitological characteristics of Schistosoma mansoni infection in swiss mice with underlying malnutrition.

The effects of a protein-restricted diet (8% protein, 81% carbohydrate and 11% lipids) on Schistosoma mansoni infectivity, fecal egg excretion and intestinal egg distribution in Swiss (SW) mice were studied. Pregnant mice received a deficient diet from the middle of gestation until delivery. Seven-days-old mice were exposed to 50 cercariae (BH strain, Brazil). Offspring mice had a free access to the deficient diet since lactation until adulthood. The controls were fed with a commercial mice diet. A parasitological examination was performed between six and eight weeks post-infection while both groups were necropsied one week later. Mice on the experimental diet showed a significant loss in body weight. There was no significant difference (p > 0.05) in pre-patent period, kinetics of egg excretion and worm recovery from mice on either diet. Significant differences (p < 0.05) were found concerning to the percentage of deposited eggs in the distal segment of the small intestine from hosts on the experimental diet. Our data suggest that experimental malnutrition induced for a long term has no detrimental effect on the acute schistosomiais infection in SW mice.

Animals↗
PubMed2004

Comparison between splenic and lymph node aspirations as sampling methods for the parasitological detection of Leishmania chagasi infection in dogs.

The sensitivities of spleen and lymph node cultures for the diagnosis of canine visceral leishmaniasis were compared in 64 anti-Leishmania antibody positive dogs from an endemic area in Brazil. The sensitivity of spleen cultures for Leishmania detection was 97.9%; in lymph node cultures it was 25%. Positive spleen culture was more frequent (p = 0.048, Fisher's exact probability test) in symptomatic (28 out of 33 animals) than in asymptomatic animals (19 out of 31 animals). These results support the use of spleen instead of lymph node aspiration as the choice method for the parasitological diagnosis of the infection.

Animals↗
PubMed2003

Parasitologic analyses of the sifaka (Propithecus verreauxi verreauxi) at Beza Mahafaly, Madagascar.

A cross-sectional parasitologic survey of a population of wild sifaka (Propithecus verreauxi verreauxi) was conducted at the Beza Mahafaly Special Reserve in southwest Madagascar. Ninety fecal samples were collected from thirty 1- to 30-yr-old male and female sifakas, and the formalin-preserved and polyvinyl alcohol-preserved specimens were examined using the zinc sulfate flotation and formalin-ethyl acetate sedimentation techniques. No intestinal parasites were recovered, possibly because the sifakas are arboreal in a dry, riverine habitat and lack human contact. Low rates of parasitic infection may have contributed to the evolution of later age at first reproduction and longer reproductive lifespan, for body mass, in Propithecus compared with other placental mammals.

Acetates↗
PubMed2003

Parasitological analysis of Leonese royalty from Collegiate-Basilica of St. Isidoro, León (Spain): helminths, protozoa, and mites.

The royal burial chamber of what is today the Collegiate-Basilica of St. Isidoro in León, Spain, built and remodeled between the 10th and 13th centuries and in the 20th century renamed the Kings' Pantheon, has 13 royal tombs that were opened in the presence of the Abbot-Prior of the Collegiate to enable a group of researchers to obtain all possible information from the royal remains. Several samples were sent to the Parasitology Unit of the Animal Pathology (Animal Health) Department at the Veterinary Faculty of León (Spain). In all the tombs, eggs and remains of nonparasitic mites were observed. In a piece of linen cloth from the bottom of 1 tomb, an Anoplocephala perfoliata egg was found. Furthermore, 4 mummified bodies were found. In 2 of these, those belonging to Infantes María and Fernando, Ascaris lumbricoides eggs were found and in the latter Trichuris trichiura eggs. We have not found in the literature reviewed any records of studies of this kind carried out in Spain.

Animals↗
PubMed2002

Adapting a case-based, cooperative learning strategy to a veterinary parasitology laboratory.

INTRODUCTION: Third-year veterinary students participate in a parasitology laboratory for instruction in diagnostic techniques. Course instructors adapted a case-based, cooperative learning approach to stimulate student involvement. Previously, students worked individually but shared common equipment in small groups. Peer interactions and discussions were not inherent in the format. Specimens were provided for practicing diagnostic techniques. METHODOLOGY: Students were assigned to cooperative learning groups of four students. Within each group, members were assigned distinct roles that rotated daily. Samples were presented as clinical cases, including history and signalment. Within groups, students performed role-specific duties and were expected to teach their component to other group members. Groups worked up their case for presentation to the class at the end of each period. Grading was unchanged from previous years, based on four individual quiz scores, two case reports, and a final practical exam. RESULTS: Student grades remained satisfactory and student feedback was highly favorable, the most common response being that group work enhanced understanding and that a case-based approach provided valuable clinical insights. An important comment was that peer teaching could be inconsistent; some students were concerned that important information was overlooked during the reciprocal teaching. Their recommendation was to verbalize expectations more clearly and to work with groups to facilitate reciprocal teaching.

Animals↗
PubMed1970

Parasitological Studies Of Korean Forces In South Vietnam: I. Examination Of Blood Films On Malaria Patients.

A parasitological study was performed with 452 malaria patients evacuated from South Vietnam by examinations of their peripheral blood. Results were as follows: 1)The peripheral blood examinations revealed that 52.0% of the examined have parasitemia, of which 95.3% was P. falciparum, one case of P. vivax and the other 10 patients were mixed infected. Neither P. malaria nor P. ovale were found. 2)A total of 1,500 thick and thin blood films was prepared and 707 slides of them (47.1%) showed positive. In P. falciparum, ring forms were found most frequently and the next was gametocytes. Eighty slides (50%) showed mixed together with both ring form and gametocytes. All of the erythrocytic stages were seen in three slides of P. vivax. 3)Weekly periodical examinations showed 233.8 parasite density every 1,000 W.B.C count in average, while occasional at fever attacks 531.7. 4)Size of gametocytes in P. falciparum was 9.31(+/-0.89) by 2.16(+/-0.53) in macrogametocyte and 6.61(+/-0.82) by 2.51(+/-0.35) in microgametocyte. Their sex ratio was 100 : 92. 5)Repeated blood examinations showed increased detection rates. The positive rate of parasitemia was 52.0% in single examination, increasing in succession with repetitions.

Journal Article↗
PubMed1981

Serologic and parasitologic studies of Entamoeba histolytica in El Salvador, 1974-1978.

Serologic and parasitologic studies were done in El Salvador, C.A., from 1974-1978 to examine the reliability of the diagnosis of Entamoeba histolytica infection in an endemic area and to confirm the estimates of morbidity and mortality due to amebiasis. The results suggest that infection with E. histolytica is common, but the estimated prevalence is too high. Misdiagnosis occurring in hospital and public health laboratories was documented. Data collected from examining family members of persons with E. histolytica infection and disease indicate that most infections are asymptomatic, and support the hypothesis that estimates of morbidity and mortality rates are excessive.

Adolescent↗
PubMed1982

Endemic filariasis on a Pacific island. I. Clinical, epidemiologic, and parasitologic aspects.

The clinical and parasitologic aspects of filariasis were investigated in 459 inhabitants of a South Pacific island endemic for subperiodic Wuchereria bancrofti filariasis. Episodes of filarial fevers, usually with concomitant lymphangitis and/or lymphadenitis, were experienced by 26%. Lymphobstructive lesions, manifest in the later decades of life, were present in 12 with elephantiasis and 24 with hydroceles. Microfilaremia was detectable by membrane filtration of 1 ml of blood in 33% of persons, with a quarter of these having less than 50 microfilariae/ml. Microfilaremia and filarial fevers were more frequent in males than females and in residents of the most inland villages. Neither presence nor magnitude of lymphadenopathy correlated with other manifestations of filariasis except that markedly enlarged inguinal-femoral nodes were more common in those with elephantiasis or hydroceles. A history of filarial fevers did not correlate with presence of microfilaremia. Over 70% of adults had microfilaremia and/or historical or physical manifestations of filariasis. The absence of detectable microfilaremia in many residents with clinical evidence of filariasis and the presence of asymptomatic microfilaremia emphasize the limitations in relying only on microfilaremia rates or clinical findings in the study of the prevalence or manifestations of filarial infection.

Adolescent↗
PubMed1984

Parasitologic and clinical features of bancroftian filariasis in a community in East Sepik Province, Papua New Guinea.

Bancroftian filariasis has been reported in several areas of Papua New Guinea. The epidemiologic features and natural history of Wuchereria bancrofti infection in this geographic region, however, have not been well-defined. The objective of this study was to assess the parasitological and clinical features of bancroftian filariasis in a community in East Sepik Province, Papua New Guinea. In a village of 99 individuals, the overall prevalence of microfilaremia was 68%. The microfilarial carrier rate was high in those less than or equal to 10 years (62%), remained elevated in the 11-20, 21-30, and 31-40 age groups (42-55%), and peaked in subjects greater than or equal to 41 years old (90%). The geometric mean level of parasitemia in all subjects with patent infection was 3,198 microfilariae/ml blood. This value was 78 parasites/ml in the less than or equal to 10-year-old age group, increased to 1,753 in 21 to 30-year-olds and was markedly elevated in subjects greater than or equal to 41 years old (6, 792 microfilariae/ml). Acute symptoms of filariasis (lymphadenitis and lymphangitis) were initially noted in individuals between the ages of 11 and 20 years (30%). Obstructive disease, manifested as elephantiasis and hydroceles, was present in 64 and 79% of 31-40 and greater than or equal to 41-year-olds, respectively. These data suggest that intense transmission of W. bancrofti infection occurs at an early age in this area of East Sepik Province; patent infection remains high in older age groups. Irreversible lymphatic obstruction develops 20-30 years after initial infection and may be associated with either amicrofilaremia or microfilaremia.

Adolescent↗
PubMed1985

Parasitologic and immunologic studies of experimental Plasmodium falciparum infection in nonsplenectomized chimpanzees (Pan troglodytes).

Parasitologic, hematologic, and immunologic parameters were monitored in intact (nonsplenectomized), adult chimpanzees infected with a "chimp-adapted" strain of Plasmodium falciparum. Following primary and secondary injections of 10(9) P. falciparum-infected erythrocytes, each chimpanzee developed a low grade parasitemia (up to 1,000/mm3) and maintained the infection without evidence of eliminating the parasites. Hematologic and serum biochemical values, as well as the majority of immunologic parameters tested, remained unaltered in infected chimpanzees. However, 2 weeks after infection T cells from infected chimpanzees demonstrated an enhanced response in vitro to stimulation with the mitogen PHA, and monocyte phagocytic activity for antibody-coated erythrocytes (Fc-mediated phagocytosis) increased significantly. During malarial infection, apes developed a strong T cell proliferative response to P. falciparum antigens and monocytes showed enhanced phagocytic activity for P. falciparum-infected erythrocytes in the absence of immune serum. These results suggest that cellular immune mechanisms, especially macrophage activation, may help control, but not eliminate, P. falciparum malaria in chimpanzees.

Animals↗
PubMed1986

Nonresolution of an amebic liver abscess after parasitologic cure.

A 43-year-old Filipino male was admitted to a Manila hospital with a 1 month history of epigastric pain and fever, and was found to have a palpable epigastric mass. Computerized tomography revealed a large hepatic abscess which serologically was shown to be amebic. Chemotherapy resulted in clinical cure and an initial reduction in size of the liver abscess. However, resolution of the abscess cavity did not occur, and on closed needle aspiration, 80 cc of characteristic amebic pus was recovered. Parasitological cure without complete repair of the abscess cavity itself raises questions concerning the potential danger of clinically silent residua and the role of therapeutic aspiration in the management of amebic liver abscesses.

Adult↗
PubMed1987

Onchocerciasis in southwestern Sudan: parasitological and clinical characteristics.

Parasitological and clinical observations were made on residents of Pongo Nuer, a village in the province of Bahr El Ghazal, southwestern Sudan. Of 202 skin biopsies, 189 (94%) were positive for microfilariae of Onchocerca volvulus. Nodules were most common around the pelvic girdle and rare on the limbs or head. Microfilarial intensities, ranging up to 1,094 mf/mg of skin, were highest at the iliac crest and shoulder; they increased rapidly in childhood but then appeared to reach a plateau maintained through adult life. Nodule presence and number, especially at multiple sites, was significantly related to skin microfilarial intensity. Dermal manifestations of O. volvulus infection were widespread and severe, ranging from acute maculopapular eruptions to chronic, diffuse, and degenerative changes, even in young adults. However, high skin microfilarial intensities were found in asymptomatic individuals; conversely, lowest intensities were in those with severest maculopapular lesions, suggesting that host response was a major determinant of disease outcome. Microfilariae were detected in the cornea or anterior chamber of the eyes of one third of those examined in all age groups, but lesions of the posterior segment, including optic neuritis, chorioretinitis, and pigmentary abnormalities, were considered responsible for visual deficits in the population sample. Some pathologic changes in the anterior segment attributable to microfilariae were more common in the young than in adults but there was no preponderance of sclerosing keratitis in adults, contrary to expectations in hyperexposed individuals in a Sudan savannah zone. The best correlate of the presence of microfilariae in the eye was the intensity of infection in shoulder skin snips. Little value could be derived from data on outer canthus samples, either in terms of severity of ocular infection or disease. Microfilaremia was common (76%) but in only one case was attributed to O. volvulus; the remainder were due to Mansonella perstans.

Adolescent↗
PubMed1988

Parasitologic and clinical efficacy of 25 and 50 mg/kg of chloroquine for treatment of Plasmodium falciparum malaria in Rwandan children.

The standard chloroquine treatment for Plasmodium falciparum malaria is 25 mg (base)/kg (C25) given over 3 days. In Rwanda, 50 mg/kg (C50) administered over 6 days has been recommended by the Faculty of Medicine, Ministry of Health. The present study compared clinical and parasitological efficacy and side effects of C25 and C50 in children less than or equal to 5 years of age. In vitro studies with chloroquine, mefloquine, pyrimethamine, and quinine were also performed. Ninety children were given a 3-day treatment of C25 and 48 a 5-day treatment of C50. Cases were followed for a total of 15 days (D0 to D14). At day 14, 73% of the C25 and 67% of the C50 children were still parasitemic, but the mean geometric parasite density had decreased by at least 96% in both groups. Clinically, 44 C25 and 12 C50 children had fever on day 0; by day 14 only 4 (9%) C25 and 4 (33%) C50 children still had fever. Side effects were found to be minimal. The chloroquine in vitro tests corroborated the in vivo findings. P. falciparum was found to be quite sensitive to mefloquine and quinine, but showed a high (59%) resistance to pyrimethamine.

Animals↗
PubMed1993

A study of onchocerciasis with severe skin and eye lesions in a hyperendemic zone in the forest of southwestern Cameroon: clinical, parasitologic, and entomologic findings.

Prior to the initiation of an onchocerciasis control program based on the mass administration of ivermectin in the rain forest of southwestern Cameroon, a preliminary baseline study of the area was conducted. The results of this study showed that onchocerciasis was hyperendemic in the area. Skin symptoms and signs were observed including pruritus (67.4% of the population examined), onchocerca nodules (51.6%), skin depigmentation (18.5%), and hanging groins (5.7%). Except for pruritus, the prevalence of these symptoms increased with age. Of the eyes examined, 44.9% had microfilariae in the anterior chamber, 33.5% had choroidoretinitis, 28.0% had punctate keratitis, 8.3% had papillary abnormalities, and 3.6% had sclerosing keratitis. Vision in 10.5% of the eyes examined was classified as blind or very poor (visual acuity = 0-0.10), in 15.7% as poor (visual acuity = 0.11-0.39), and in 73.8% as good (visual acuity = 0.4-1.00). Unlike previous reports that have linked serious ocular damage mainly to savanna onchocerciasis, the present study showed that forest onchocerciasis also caused significant ocular pathology, including blindness. Parasitologically, positive skin snips were recorded for 92.7% of the persons examined, with both sexes being equally infected. The parasite load, expressed as the geometric mean number of microfilariae per skin snip, was 53.6, and was much higher in males than in females. The flv vector, Simulium squamosum, had a high infection rate of 7.5% infective females in Bakumba and 6.8% infective females in Ngbandi, the two fly-catching points. The transmission potential was 266 infective larvae per person per month in Bakumba and 189 in Ngbandi.

Adolescent↗
PubMedDate not supplied

Canine visceral leishmaniasis in Colombia: relationship between clinical and parasitologic status and infectivity for sand flies.

We studied the reservoir competency of canines with distinct clinical presentations of Leishmania chagasi infection. The parasitologic status of asymptomatic and symptomatic dogs was determined by standard culture methods Infectivity was assessed by multiple xenodiagnoses with Lutzomyia longipalpis, over a period of 2-11 months. Asymptomatic dogs were non-infective (0 of 5) while 2 of 7 oligosymptomatic dogs infected L longipalpis, transmitting the parasites at low rates (range 0.9-5.2% of engorged flies). Polysymptomatic dogs transmitted L. chagasi more frequently (4 of 8 dogs) and reached higher infection rates (range 5.0-22.5% of engorged flies). The skin of the ear tended to be more infective to sand flies than that of the abdomen. Polymerase chain reaction hybridization (PCR-H) was a sensitive method for detection of L. chagasi, yielding the highest positive rate in serum (16 of 17 dogs) with no distinction between clinical groups. No association between skin positivity by PCR-H and infectivity to sand flies was found. The infectivity of dogs from clinically comparable groups from Colombian and Mediterranean foci differed. This may be a reflection of varied nutritional conditions or vector competency of distinct sand fly species.

Animals↗
PubMed2002

Impact of the malaria control campaign (1993-1998) in the highlands of Madagascar: parasitological and entomological data.

Malaria transmission in the central highlands of Madagascar was interrupted in the 1960s by a national control program that used DDT indoor spraying and mass treatment with chloroquine. At the end of the 1980s in this region, epidemic malaria reappeared. Italian health authorities provided technical assistance to the National Malaria Control Program since the beginning of the resurgence of malaria in the central highlands. Yearly residual house spraying performed for 5 years (1993-1998) and the availability of antimalarial drugs reduced malaria transmission to very low levels, with improvement in parasitologic and entomologic indexes. A significant reduction of malaria prevalence was observed in the villages located at altitudes of 1,000-1,500 m, corresponding to the stratum of unstable malaria that was the main target of the antivector interventions. A significant reduction of malaria prevalence was also observed in the villages located at altitudes of 900-1,000 m, where malaria transmission is stable. The main vector Anopheles funestus was dramatically reduced in abundance and distribution in the sprayed areas.

Adolescent↗